Southern California Section

September 2008 Meeting Summary

On September 11, 2008, the Southern California Chapter of the ION held a meeting, hosted by NavCom in Torrance, CA. The meeting included a presentation from Dr. Todd Walter of Stanford University entitled The Ionosphere and its Effect on Satellite Navigation. About 50 people were in attendance for the meeting. A short biography and abstract of the meeting follows, and the slides used during the meeting are attached.

Biography of Dr. Todd Walter
Dr. Todd Walter received his B.S. in physics from Rensselaer Polytechnic Institute and his Ph.D. in 1993 from Stanford University. He is currently a senior research engineer in the Department of Aeronautics and Astronautics at Stanford University. He is active in the development of the Minimum Operational Performance Standards for WAAS (Wide Area Augmentation System) and co-chair of the WAAS Integrity Performance Panel focused on the implementation of WAAS. He has served as program chair and general chair for the ION's NTM and GNSS meetings and is currently the western regional vice president. He was a co-recipient of the 2001 ION early achievement award and is a fellow of the ION.

Abstract of Todd Walter's Talk (presentation slides)
The ionosphere creates some of the most significant challenges to the use of precise GPS. Its spatial and temporal variations limit the accuracy of position solutions. The uncertainty of its influence limits the availability of high accuracy and high integrity systems. In equatorial areas the ionosphere can cause a form of self-interference, called scintillation, that can prevent the tracking of the signal altogether. Yet, despite these serious obstacles, the ionosphere itself is not well understood. As the use of GPS becomes more demanding and more wide-spread, it is important to examine the ionosphere and understand the range of possible effects.

The FAA has a network of redundant measuring stations throughout North America that has been used to continuously observe ionospheric behavior for the last 8 years. These data have been used to identify the largest gradients observed at middle latitudes.

Our emphasis, in this research, has been on identifying the extreme behavior that, fortunately, occurs rarely over the United States. We have also examined data from other parts of the globe where large variations can be much more common.

A partial solution to the challenges from the ionosphere is under development in the form of modernization of the GPS signals. However, this solution comes at a cost: the combination of signals to create an ionospheric-free measurement greatly inflates the magnitude of other error sources. Users who are particularly affected by the ionosphere will welcome these new signals that will do much to reduce extreme behavior.

This talk will focus on observations of ionospheric effects ranging from typical observed variations to the extreme behavior of ionospheric superstorms. The effects on satellite navigation will be discussed as well as how to place confidence limits on the possible magnitude of its effect.

April 2008 Meeting Summary

The Institute of Navigation Southern California Section meeting was held on April 23, 2008. Per Enge of Stanford University gave a presentation titled Modernized GPS for Worldwide Vertical Guidance of Landing Aircraft.

November 2007 Meeting Summary

The Institute of Navigation Southern California Section meeting was hosted by Navcom and held in Torrance on November 15, 2007. At the meeting, new officers were elected to serve as follows:

Chairman: Jerry Knight, NAVCOM Technologies

Vice Chairman: Len Jacobson, GSAM Inc.

Executive Secretary: Cecelia Feit, Raytheon

Treasurer: Ray DiEsposti, General Dynamics

Publicity Officer: Steve Rounds, L-3 Communications/IEC

Program Director: James Litton, Jim Litton Consulting Group

Scholarships and Student Program Chair: Kevin Rudolph, Raytheon

Immediate Past Chairmen and Section Founder: Clyde Edgar

Jerry Knight spoke on behalf of his coauthors, Charles Cahn and Sidharth Nair, presenting the results of their research entitled, "A New Anti-Jamming Method for GNSS Receivers."


Incoming Chairman, Jerry Knight presented a token of appreciation to outgoing chairman Clyde Edgar.

March 2005 Meeting Summary

The Institute of Navigation Southern California Section meeting was hosted by The Aerospace Corporation and held in El Segundo on March 31st. At the start of the meeting the Southern California section chair, Clyde Edgar and California Polytechnic University Advisor, Dr. Ilir Progri presented a ION scholarship award to Lijia Chen, the first Southern California section ION graduate scholarship award recipient as part of the ION student outreach program. Next, our distinguished guest speaker John Lavrakas, ION Western Region Vice president, spoke about the ION, its purpose, membership benefits, and the role it plays in furthering the art and science of navigation. John then followed with a technical presentation on GPS "An Overview of Civil Monitoring". The meeting was well attended and was followed by an spirited question and answer period. Please see the following documents for more information:

The ION and Membership Benefits, John Lavrakas, ION Western Region VP.

An Overview of Civil Monitoring, John Lavrakas, Overlook Systems.

Left to Right: Clyde Edgar, SoCal Chair, Professor Ilir Progri, CPU Student advisor, John Lavrakas, ION Western Regional VP, Line Moisan, Scholarship Chair, Lijia Chen, Graduate scholarship award winner

October 2004 Meeting Summary

The Institute of Navigation Southern California Section October 20 meeting was hosted by Boeing Space Systems and held in the Boeing Seal Beach Complex, Building 86. The meeting was well attended even though freeways were flooded and a large amount of rain was falling. Mr. Frank Czopek, GPS Block II/IIA Satellite Program Manager, presented an historical overview of the GPS satellite program at Seal Beach and showed slides of the manufacturing floor facilities in its heyday.

After his very interesting presentation Frank led a walking tour of the facilities highlighting the immense Thermo-Vac Chambers, Spin table, and Manufacturing room area. He described what the areas were like during the 3 shift GPS SV manufacturing schedule and also discussed a little known incident by eco-terrorists that resulted in actual damage to a space vehicle, the infamous ax incident where a space vehicle was attacked and damaged with an ax.

The tour ended with a viewing of a glass encased chrome plated shovel, the shovel that Werner Von Braun used to dedicate the facility for the Saturn Project in 1966. The property used for manufacture of the Block I, II and IIA satellites is designated to be sold later this year as it is surplus to Boeing's needs. The meeting attendees grouped around the Navstar Monument for a photograph at the end of the meeting. The monument depicts each satellite manufactured in the facilities and when it was launched.

April 2004 Meeting Summary

The Institute of Navigation Southern California Section meeting held on Thursday, April 22 was well attended and hosted by Raytheon in El Segundo. 1Lt. Bryan Titus of the GPS JPO spoke on behalf of Mr. Tom Stansell on "The L1C Stewardship Project", an IGEB sponsored program to actively solicit inputs from interested parties on the implementation of the new GPS L1C signal. The Interagency GPS Executive Board (IGEB) has funded the stewardship project (L1C Project) to determine how best to improve the L1 civil signal on GPS III satellites. The GPS JPO and the USGS in Pasadena are co-sponsors of the project.

A key purpose is to determine what users and companies want in a new signal structure. This is historic, because for the first time the U.S. Government is seeking advice and comment from experts around the world on a proposed new civil signal. 1Lt. Titus requested that the presentation and questionnaire form be made available to the ION website and welcomes questionnaire inputs.

L1C Brief

L1C Questionnaire